Laser

Laser Weapons Will Turn Earth's Atmosphere into Lenses, Deflector Shields

BAE Systems has been working on a way to use lasers to actively reshape the atmosphere to turn it into a variety of optical tools. The Laser Developed Atmospheric Lens system (LDAL) uses powerful laser pulses to make air itself into lenses, mirrors, and even protective deflector shields.

Those bubbles and layers of hot air that annoy telescopes are bad only because they're random. LDAL’s pulsed lasers generate their own bubbles of hot air in a controlled way. When these hot air bubbles are layered on top of colder air, the change in density refracts light that passes through. This phenomenon is exactly where mirages come from, and fundamentally, this is how a traditional lens works as well. The only difference is that most lenses use solid materials (glass or plastic) instead of air, because solids are much easier to structure and control.